Method and system for walkway with unsupported end

ABSTRACT

Methods and systems for stairways or other walkways supported at only one end provide a plurality of stair treads are attached to a support beam, a pair of mounting brackets disposed at either side of a support beam bottom end rotatably connected to the support beam by a pivot bolt, the mounting brackets connected to a base, the base connected to a load bearing structure. A support bolt is disposed through the mounting brackets and below a bottom surface of the support beam. Locking means pivotally connected to the support beam engage a base mounting plate and restrain the stairway from at least one of pivoting upward about the pivot bolt or pivoting downward about the pivot bolt. Operative loads transfer from the support beam into the support brackets through the pivot bolt and support bolt and through the base into the load bearing structure.

FIELD OF THE INVENTION

The present application relates to methods and systems for moving between first and second noncontiguous locations. More particularly, the present invention is related to stairway, gangways, ramps and other fixtures configured to support a person walking thereupon, wherein a first end of the fixture is affixed to a first location, and another end may be unsupported.

BACKGROUND OF THE INVENTION

A variety of stairway, ladder, ramps, gangway and other personal conveyance structures are known and proposed for enabling a person to move from one location to a second non-continuous location. Bridge and ramp structures are commonly used to move from one location to another second location across a surface discontinuity such as gap or chasm or where surface changes occur (e.g. land to water), and in particular where the first and second locations are substantially on a common vertical level. Where the first and second locations are located on substantially divergent vertical levels relative to each other, stairways and ladders are more commonly used, and thus enabling a person to move both laterally and vertically as the person travels from the first location to the second location.

What is important in such structures is that they are physically resilient and strong enough to support the weight of the person or persons traveling thereupon, as well as also supporting the weight of any other articles been conveyed there with. One technique for ensuring structural integrity of the conveying structure is to connect each end of the structure to the two locations: thus a bridge, stairway or ramp is physically supported by each of the first entry and second exit locations, and therefore each end of the structure may bear operative loads and transfer said loads through structural connections to each location.

However, problems with this conventional load bearing and sharing arrangement arise where one of the two locations may be unfixed or otherwise movable or moving relative to the other location. For example, a first location may be a fixed structure such as a landmass shoreline or a dock connected thereto, and the other second location may be a boat floating in a body of water. Wind and wave forces acting upon a boat also generally compel the boat to move toward and away from the fixed shoreline or dock, and therefore some element of the ramp/stairway, shoreline and boat assembly must either resist these forces or move in reaction thereto. Resisting these movement forces may cause damage to the boat, shorelines structure or the ramp/stairway, perhaps even leading to failure of the assembly. It is also known that rigid or inflexible connections tying boats to shorelines may also have the unintended consequences: boats have been known to sink if unable to move relative to the shoreline in response to heavy rains, storm surges or flooding, and strong wave or wind forces.

Therefore, it is generally desirable that some part of the first location/ramp-or-stairway/second location assembly incorporates a flexible and movable element, allowing movement of the first location relative to the second location. Since a boat will generally be moving relative to a fixed shoreline or dock structure, for example due to wave, wind and other forces acting upon a floating boat, a boarding ramp/stairway may also move correspondingly if one end is fixed to the boat. However, such movements of the ramp or stairway may be hazardous to a person trying to navigate the rent or stairway while moving, presenting a trip or fall hazard and thereby perhaps causing injuries to a person thereupon.

In an alternative instance the ramp/stairway may remain fixed relative to the first shoreline location and an end of a ramp/stairway resting upon a boat may be allowed to move or slide along a boat structure. However, in this instance the stairway or ramp may still be compelled to move vertically or horizontally with corresponding movements of the boat, thereby presenting a slip, trip or fall hazard to a person thereupon or causing damage to either the ramp/stairway or the boat in resisting this movement. And the boat may be damaged by forces exerted on the boat at the interface of the ramp or stairway.

Moreover, another hazard is presented by forces compelling the ramp/stairway to move vertically as well as horizontally in reaction to a moving boat. For example, as it is generally desirable that the stairway have stair treads oriented horizontally for walking, and that a ramp have a walking surface oriented generally horizontally, changing the vertical orientation of the stairway or ramp may result in dangerous angles of the stair treads or ramp surface relative to a level horizontal orientation and, again causing a slip and fall hazard.

In view of the foregoing, there exists a need for a solution that solves at least one of the deficiencies of the related art.

SUMMARY OF THE INVENTION

The present application relates to methods and systems for stairways or other walkways supported at only one end. In said methods and systems a plurality of stair treads are attached to a support beam. A pair of mounting brackets disposed at either side of a support beam bottom end is rotatably connected to the support beam by a pivot bolt, the mounting brackets further connected to a base, the base connected to a load bearing structure. A support bolt is disposed through the mounting brackets and below a bottom surface of the support beam. And a locking means is pivotally connected to the support beam and configured to engage a base mounting plate and thereby restrain the stairway from at least one of pivoting upward about the pivot bolt or pivoting downward about the pivot bolt. The support beam is configured to pivot downward about the pivot bolt to rest upon the support bolt in a downward deployment and pivot upward about the pivot bolt into a non-deployed orientation. And the support beam is configured to transfer operative loads upon the stair treads aligned in the support beam downward deployment and with an opposite upper support beam end unsupported from the support beam bottom end through leverage into the support brackets through the pivot bolt and support bolt, the support brackets thereby configured to transfer all the stair tread operative loads through the base into the load bearing structure, and wherein said upper beam end is free of connection to the base or the load bearing structure or any other operative load-supporting structure.

In one aspect stairway pivotally connected locking means comprise a lock bar having a top end and a bottom edge, the lock bar top end defining a bolt aperture, and a pivot bolt rotatably conveyed through the pivot bolt aperture. The support beam defines an aperture slot projecting inward from a support beam bottom edge and configured to allow the lock bar to pivot downward and into the aperture, and a mounting plate is disposed between the support brackets and the base. Thus the lock bar is configured to hang downward from the pivot bolt within the support beam aperture slot and form an inward negative vertical locking position angle with respect to a vertical orientation parallel to a gravitational force vector, the lock bar bottom edge thereby aligned above and spaced from a top surface of the base mounting plate, and wherein pivoting of the support beam upwards about the pivot bolt causes the lock bar bottom edge to be driven into base mounting plate top surface, the lock bar thereby constraining the stairway support beam from moving upward.

In another aspect an inward negative vertical locking position angle is chosen to cause the lock bar bottom edge to be pivoted and driven toward and along the bottom plate surface along an angle vector component in response to forces raising the stair upward about the pivot bolt, the vector component urging the lock bar bottom edge into engagement with the bottom plate surface and thereby preventing the lock bar bottom edge from moving in a direction opposite to the angle vector component and slipping off of the plate surface and out of an engagement with the plate surface.

In one aspect base structures may comprise a riser configured to enable access to the locking means and to enable operative movement of the locking means without interference with the load bearing structure, and a first step connected to the riser and spaced a lock bar receiving gap from the support brackets and the base mounting plate, wherein the lock bar is configured to pivot outward and away from alignment of the lock bar bottom edge over the mounting plate top surface and to drop into the lock-arm receiving gap when the stairway is lifted upward.

In another aspect at least one support beam bottom edge stopper may be attached to at least one of the support brackets, wherein the support beam bottom edge rests against the stopper when the stairway is deployed in an upward/stowed position with a bottommost stair tread front edge spaced from the first step. In some embodiments the stopper is an eccentric cam. And in some embodiments the lock bar bottom edge spacing distance is from about 0.005 inches to about 0.007 inches, and the inward negative vertical locking position angle is from about six degrees to about seven degrees from the vertical orientation.

In some embodiments the lock bar pivot bolt aperture is formed off-center in the lock bar top end more proximate to an inside edge of the lock bar then a lock bar outside edge arrayed facing the lock bar receiving gap, the off-center alignment configured to cause the lock bar to hang downward from the pivot bolt and form the inward negative vertical locking position angle in response to gravitational forces acting on the lock bar along the vertical orientation.

In some embodiments a lock bar arm is rotatably attached to the lock bar, a spring-loaded means is attached to the lock bar arm and configured to urge the lock bar arm and the lock bar inward toward the mounting plate, and a pedal means is attached to the lock bar arm and configured to move the lock bar arm and the lock bar outward away from mounting plate in response to a user pushing the pedal means, the outward lock bar movement causing the lock bar to pivot outward and into an alignment enabling the lock bar to drop downward into the lock-bar spacing gap with pivoting of the stairway upward. In some embodiments the lock bar comprises an internal lock bar notch having a lower lip, and further in some embodiments the spring-loaded lock bar arm is configured to drive an internal lock bar notch surface into contact with an inner edge surface of the base mounting plate and dispose the notch lip spaced below a base mounting plate lower surface a lip spacing distance. In some embodiments the lower lip is oriented at a positive angle with a horizontal orientation normal to the vertical orientation, and further in some embodiments the lower lip horizontal orientation angle is about 10 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings in which:

FIGS. 1 a and 1 b are side views of a stairway according to the present invention.

FIG. 2 is a top view of the stairway of FIGS. 1 a and 1 b.

FIG. 3 is a side detail view of a portion of the stairway as illustrated in FIG. 1 a.

FIG. 4 is a side detail view of a portion of the stairway as illustrated in FIG. 1 b.

FIG. 5 is a bottom front view of portions of the stairway of FIGS. 1 a, 1 b, 2, 3 and 4, shown as partially disassembled for clarity.

FIG. 6 is a top view of a ramp according to the present invention.

FIG. 7 a and 7 b are side views of the ramp of FIG. 6.

FIG. 8 is a side detail view of a portion of another embodiment of a stairway according to the present invention with some elements omitted for clarity

FIG. 9 is a side detail view of portions of the stairway portion of FIG. 8, shown as partially disassembled and with some elements omitted for clarity.

FIG. 10 is a side detail view of portions of the stairway portion of FIG. 8 in an upward/stowed deployment configuration, shown as partially disassembled and with some elements omitted for clarity.

The drawings are not necessarily to scale. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. The drawings are intended to depict only typical embodiments of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 a and 1 b illustrate a stairway 100 according to the present invention, wherein FIGS. 3 and 4 provide enlarged views of a bottom area 108 of the stairway structure 100 as illustrated in FIGS. 1A and 1B, respectively. The stairway 100 has a single support beam 102, which supports a plurality of stair elements 104 each comprising a generally planar stair tread plate 106 attached to a tread support member 114, wherein the stair tread surfaces 106 are aligned generally parallel to each other. The front edges 107 of the stair tread plates 106 preferably overhang the tread support members 114 and thereby provide a stair-climbing array optimized for walking upon; the overlapping and parallel stair tread plate 106 alignment also shown from a top view in FIG. 2.

The stair elements 104 are preferably parallel to a horizontally flat walking or stare-climbing surface orientation as defined by gravity when the deployed in a down position as shown in FIG. 1A. Thus in one embodiment the support beam 102 forms a working angle β1 with a horizontal ground orientation and the stair treads 106 form a working angle β2 with the linear-rectangular support beam 102, wherein β1 and β2 have similar or equivalent values; however, other angles β1 and/or β2 may be selected, for example through component dimension selections described below, and the present invention is not limited to the examples presently described.

The tread support members 114 are each supported at a front end by a pair of support arms 112 bolted to the support beam 102 and at a back end by a tread support connection means 116. In the present embodiment the tread support connection means 116 comprises a hexagonal mounting cylinder element 118 bolted to the tread support member 114, wherein the hexagonal mounting cylinder element 118 is itself bolted to the support beam 102 so that one of its six flat faces 120 is aligned with and fixed against the support beam 102.

One advantage of the stairway at 100 is that it is structurally attached in to a first ground surface or other base structural element 101 at the bottom 108 of the stairway 100, and that the stairway upper end 110 is unsupported: more particularly, the stairway 100 bottom connecting structure 108 is configured to transfer all of the operational loads of stairway to the ground or base structural element 101, allowing the upper end 110 to remain free of connection to a second ingress or egress location moving or movable relative to the base structural element 101, such as a boat deck or other second location.

A pair of mounting brackets 126 are disposed at either side of the support beam 102 and rotatably connected to the support beam 102 by a first pivot bolt 128. In the present embodiment the first pivot bolt 128 is conveyed through an aperture in one bracket 126 and screwed into a threaded receiving aperture in a receiving mounting bracket 126. A reinforcing plate 124 is attached to the bottom surface 125 of the rectangular support beam 102, for example by one or more bolt means 305, and the support beam 102/reinforcing plate 124 assembly is pivoted downward into rest against a support bolt 130. In the present embodiment the support bolt 130 is conveyed through a support bolt aperture 332 in one bracket 126 and support bolt threads engage a threaded receiving aperture in the other receiving mounting bracket 126. Thus operative loads of the stairway 100 are leveraged from the support beam 102 into the support brackets through the arrangements of the pivot bolt 128, reinforcing plate 124 and support bolt 130 structures.

Although in the present embodiment the pivot bolt 128 and support bolt 130 have threaded portions enabling easy installation, removal and replacement operations with respect to the stairway 100, they may also have solid or otherwise non-thread form to enhance their relative strength and performance characteristics. It will also be understood that the support beam 102 may have alternative structure: for example it may comprise a rectangular-shaped beam with a bottom wall omitted (not shown): such a structure has been found to remain more stable than rectangular beams 102 through variable weather, for example resisting expansion and contraction during hot weather conditions.

The mounting brackets 126 are each installed into the ground or other structural base area, for example by one or more bolting means 213 passing through a base plate 101 and into a base structural element 105, wherein the base structural element 105 is configured to receive the operational loads of the stairway 100. The base mounting element 101 may be one or more major structural elements such as a large beam or piling or concrete flooring or other anchored structure; in some embodiments the base 105 is itself a step element, having a step height relative to a base walking surface below. A handrail 140 may also be provided, generally aligned parallel to and spaced from the support beam 102 in order to provide support to one traveling up or down the stairway 100 while it is deployed downward, as is common in stairway design and sometimes specified in one or more code standards.

The stairway 100 is configured to be movable, and more particularly to be pivoted upward about the pivot bolt 128. This enables the stairway 100 to be stored upward as shown in FIG. 1B, when not deployed for use as shown in FIG. 1A. Thus in one example adapted for use in boarding a boat deck from a dock incorporating the base structural element 105, the stairway 100 may be moved up and back over the dock and out of the way of the water or the boat: the entire stairway 100 thus pivoted to the left of a vertical axis N normal to horizontal and extending upward from the inside edges of the mounting brackets 126, as illustrated in FIG. 1B. In one preferred embodiment the front edge 107 a of the bottom step tread 106 a is configured to rest upon a deck board or other base surface element 103 a distance 150 below the pivot bolt 128 and with the support beam 102 making an angle θ with the horizontal ground orientation greater than 90 degrees. This enables the weight of the stairway assembly 100 to urge the stairway 100 to remain pivoted about the pivot bolt 128 and thus upright, wherein the support beam 102 forms a positive angle δ with vertical axis N. As is readily apparent the stairway 100 must be then be lifted upward with enough force to counter the weight of the stairway 100 as leveraged through the pivot bolt 128 to move the stairway 100 back into its deployed or “down” position as shown in FIG. 1 a. Additional locking, restraining or weighted means (not shown) may also be used to provide additional forces to keep the stairway 100 in the upright/stowed position shown in FIG. 1 b.

The present handrail 140 is fixed to the stair assembly 100 support beam 102 and thus pivots upward correspondingly with movement of the stair assembly 100. In one advantage this enables to the handrail 140 to thus pivot upward and out of the way to avoid interference with or obstruction to movement about the stair assembly when the stairway 100 is pivoted upward, for example as described above, and thus the handrail 140 is configured to provide safe egress/ingress functions through enabling movement as needed. In the present embodiment the handrail 140 is illustrated as supported by alternative exemplary vertical support members: first vertical support members 142 a aligned generally normal with respect to the horizontal ground orientation when the stairway 100 is deployed in the downward position illustrated in FIG. 1A, and second vertical support members 142 b are aligned with respect to an angle 144 from normal to the support beams 102 (in one example the angle 144 is about 15 degrees downward toward the horizontal ground orientation when the stairway 100 is deployed in the downward position illustrated in FIG. 1A); and it will be understood that other handrail vertical support 142 orientations or angles 144 may be practiced.

More particularly, the orientation of the vertical support members 142 may be altered in response to one or more design requirements or parameters. For example, some applications may encounter obstructions in either or both of the downward/deployed or upward/stowed stairway 100 positions, or while traveling from one position to the other, which may require a specific handrail 140 and/or vertical support 142 orientation: examples may include selecting vertical support 142 b or 142 b orientations, or some other (not shown) handrail 140 or vertical support 142 orientation. In some applications handrail 140 and vertical support 142 may be retractable, and thus collapsed for upward/stowed positioning or stairway 100. Thus additional advantages may be provided by configuring the handrail 140 and/or vertical support 142 for mobility in order to address obstructions, egress or other functional characteristics.

The stairway 100 incorporates a locking or restraining means 160 for maintaining the stairway 100 in the downward deployed position shown in FIG. 1A by stopping the support beam 102 from pivoting upward about the pivot bolt 128, thereby preventing movement of the stairway assembly 100 upward and backward. FIG. 5 provides a front view of the bottom area 108 of the stairway 100 as partially disassembled for clarity. The restraining means 160 comprises a lock bar 464 pivotally connected to a connection block 466 attached to the top surface 127 of the rectangular support beam 102, and a lock bar engagement arm 462 extending horizontally on either side of the lock bar 464. The support beam top surface 127 further defines an aperture slot 476 projecting inward from the support beam bottom edge 470 and configured to allow the lock bar 464 to pivot downward into an inward negative-vertical locking position there within.

In a lock position the lock bar 464 forms an angle 302 with a vertical axis orientation NN normal to horizontal as defined by gravity, with the bottom edge 475 of the lock bar 464 engaging the base mounting plate top surface 111. In one embodiment the angle 302 is from about six degrees to about seven degrees. In this lock position the stair 100 cannot be pivoted upward about the pivot bolt 128, since the lock bar edge 475 would have to also pivot downward and this motion is barred by the base mounting plate top surface 111. Thus forces pivoting the support beam 102 upward and about the pivot bolt 128 are translated by the pivot bolt 128 to drive the lock bar bottom edge 475 into the bottom plate top surface 111. And in one advantage the angle 302 causes the lock bar 464 to be pivoted and driven toward the bottom plate 101 along the plate surface 111 along an angle vector component 304 in response to forces raising the stair 100 about the stair pivot bolt 128: these vector forces 304 urge the lock bar 464 into engagement with the bottom plate 101, preventing the lock bar bottom edge 475 from moving in an opposite direction to the vector 304 and slipping off of the plate surface 111 and dropping into the gap 170 and thereby out of locking engagement with the bottom plate 101. In one advantage as forces acting on the stairway 100 in an upward pivot direction increase, these forces are translated by the pivot bolt 128 into increasing forces driving the lock arm bottom edge 475 further into the bottom plate top surface 111 and urging said bottom edge 475 to slide further inward along the surface 11 along the direction of vector 304, which also increases frictional forces that must be overcome to slide the lock arm bottom edge 475 along the bottom plate top surface 111 in an opposite direction to release the locking means 160.

The negative angle 302 alignment is achieved mechanically through gravity. The lock bar 464 has a pivot bolt aperture 467 formed off-center in the top end of the bar 464, more proximate to the inside edge 468 of the bar then the outside edge 471. Thus when the bar 464 hangs downward and pivots in response to gravitational forces about the lock bar pivot bolt 476 it will hang at the negative angle 302. This provides advantages in providing a passive means for assuring that the lock bar edge 475 will swing inward and engage the base plate top surface 111: no positive or active action is required to actively engage the lock, rather gravity will cause the lock bar 464 to swing down and inward and into the lock position along vector 304 as shown in FIG. 3. This passive locking action may be enhanced by using a heavy or dense structural element for the lock bar 464 and/or the engagement arm 462: in one embodiment the lock arm 464 is a dense nickel metal alloy, however, other embodiments may also be practiced.

The arm 462 provides engagement or handle areas 474 at either end for engaging and pivoting the locking bar 464 outwards to release the restraining means 160. In this fashion the locking bar handle areas 474 may be engaged by a hand, a foot, or a rope or cable or other attachment means or mechanical means (not shown) and the arm 462 compelled outward by causing the arm 464 to pivot outward.

Thus moving the lock bar 464 outward from engagement with the base mounting plate top surface releases the restraining means 160 and allows the stairway 100 to pivot upward and backward about the pivot pin 128. In one example a gap 170 is provided between the base structural element 105 and a deck board or other base surface element 103, wherein the gap 170 is configured to receive the lock bar 464/arm 462 assembly. In this fashion thus when the lock bar 464/arm 462 assembly is pivoted outward and the stairway 100 is lifted upward the lock bar 464/arm 462 assembly drops into the gap 170 and allows the stairway 100 to pivot back toward the up position, as shown in FIG. 4.

Advantages may be provided by forming many of the components with lightweight and but structurally strong materials: this may enable a person to easily pivot the stair 100, and also reduce the amount of forces acting upon the base mounting components in supporting the stair 100 as well as persons thereupon. In one embodiment lightweight structural strength is achieved by using aluminum materials for many of the structural elements, wherein the support beam 102 is formed from a hollow rectangular extruded aluminum beam, the reinforcing plate 124 an aluminum plate having a common width 210.

Inside the aluminum support beam 102 of the present embodiment one or more aluminum reinforcing blocks 702 are provided between the bottom surface element 125, the top surface element 127 and the locking means mounting brackets 466 and proximal to the pivot bolt apertures 330, further forming a structural support assembly with bolting means 704 connecting the locking means mounting brackets 466 to the support beam 102. The aluminum reinforcing blocks 702 thus provide structural support to the support beam 102, enabling it to transfer operative loads directly to the base brackets 126 without the hollow support beam 102 collapsing. In some embodiments additional reinforcing side plates 706 are attached to the inside of the support beam 102 side walls. Lock bar engagement reinforcing blocks or other structures 708 may also be provided below the base plate 101, in order to reinforce the plate 101 against deflection, distortion, bending or other unwanted failures of the lock bar 464/base plate 101 in response to strong forces urging the stair 100 upward about the pivot bolt 128.

It will also be apparent to one skilled in the art that other materials may be used, and the present invention is not limited to the aluminum structural materials provided in the present example. Moreover, alternate embodiments may use support beams 102 having solid cross-sections (not shown).

Another advantage of the present invention is that materials and dimensions may be chosen to provide both required geometry characteristics. For example, the thickness 340 of the reinforcing plate 124 may be chosen to provide structural integrity to the stair: for example, to reinforce the support beam 102 against forces acting upon the beam 102 through the pivot bolt 128. It may also be selected to provide a desired support beam working angle β1 value: for example, keeping the location of the support bolt 130 constant results in increasing or decreasing the support beam working angle β1 in proportion to increasing or decreasing the plate thickness 340.

Where the plate thickness 340 is variable it is also preferred to provide for variances in the effective length of the support arms 112 relative to the tread support members 114 and the support beam 102, to thereby ensure that the stair treads working angle β2 may be correlated to the support beam working angle β1 to maintain desired similar or equivalent values. Thus in one embodiment a plurality of tread support member bolt holes 480 and support beam bolt holes 482 are provided for selection and use with the support arms 112. This enables the provision of different reinforcing plates 124 with different thicknesses 124, wherein respective tread support member bolt holes 480 and support beam bolt holes 482 are chosen in response to the plate thickness value 124 to define the effective length of the support arm 122 and thereby enable one to correlate the support beam working angle β1 to the stair treads working angle β2.

In some embodiments the stairway 100 may incorporate weighted means (not shown) to urge the ladder to stay downward when deployed, as a further safety to prevent unwanted tipping backwards of ladder. For example, a weight (not shown) may hang downward from the stairway 100 or associated attachment, and must be raised against gravity to raise ladder. In one boat dock example the weight means may be located in the water when deployed, adding additional water weight or resistance forces that must also be overcome in order to lift the stairway 100.

FIGS. 6, 7 a and 7 b illustrate a pivotable ramp 500 according to the present invention. The ramp 500 has a single support beam 502, which supports a uniform walkway surface 506 aligned generally parallel to a horizontally flat walking surface orientation as defined by gravity. When deployed downward the ramp 500 is supported only by connecting structure 508 at one end, the connecting structure 508 thus configured to transfer all of the operational loads of ramp 500 to a ground or base structural element 505 and allow the upper ramp end 511 to remain free of connection to a second ingress or egress location moving or movable relative to the base structural element 505, such as a boat deck or other second location.

A pair of mounting brackets 526 are disposed at either side of the ramp support beam 502 and rotatably connected to the ramp support beam 502 by a ramp pivot bolt 528 conveyed there between. A reinforcing plate 524 is attached to the bottom surface 525 of the rectangular ramp support beam 502, and the support beam 502/reinforcing plate 524 assembly rests against a base plate 501 through which the pair of mounting brackets 526 are attached to the base structural element 505. Thus the operative loads of the ramp 500 are leveraged from the support beam 502 by the pivot bolt 528 and support brackets 526 back into the base structural element 505 through the reinforcing plate 524. A handrail 540 may also be provided, preferably aligned parallel to the ramp surface 506.

The ramp 500 is configured to be movable, and more particularly to be pivoted upward about the pivot bolt 528. This enables the ramp 500 to be lifted up and stored out of the way when not deployed for use, as described generally above with respect to the stairway 100. The ramp 500 also incorporates a restraining means 560 structurally and functionally similar to the stair locking means 160 described above for restraining the ramp 500 from unintentional pivoting about the pivot bolt 528, thereby maintaining the ramp 500 in the downward deployed position shown in FIG. 7 a.

The restraining means 560 comprises a lock bar 564 with an engagement arm 562, said bar 564 pivotally connected to a connection block 566 attached to the top surface 527 of the rectangular ramp support beam 502. The support beam top surface 527 further defines an aperture 576 configured to receive the restraining means bar 564 and allow the bar 564 to pivot downward into a negative-vertical orientation about an offset pivot bolt 565, the lock bar bottom edge 578 thereby engaging a base plate top surface 580. In the downward position the lock bar 564 thus prevents the ramp 500 from unwanted movement back and upwards, in a fashion generally similar to that described with respect to the stairway lock bar 464.

Moreover, moving the lock bar 564 outward from engagement with the base plate top surface 580 releases the restraining means 560 and allows the ramp 500 to move upward and backward, again in a fashion similar to that described above with respect to the stairway 100. In one example the lock bar 564/arm 562 assembly may be pivoted all the way up until the arm 562 is generally parallel with the support beam bottom edge 570 and the lock bar 564 is clear of engagement with the base plate top surface 580. In another example a gap 590 is provided between the base structural element 505 and a deck board or other base surface element 503: thus when the lock bar 564/arm 562 assembly is pivoted outward when the ramp 500 is lifted upward the lock bar 564/arm 562 assembly drops into the gap 590 and allows the ramp 500 to pivot back toward the up position, as shown in FIG. 7 b.

FIG. 8 provides a side detail view of a portion of another embodiment of a stairway 800 according to the present invention, with some elements omitted for clarity. More particularly, a support beam is pivotally connected to a pair of mounting brackets 826 through pivot bolt 828 means and supported through elements described above with respect to FIGS. 1A, 1B, 2, 3, 4, 5; in the present view the inside bracket of the pair of mounting brackets 826 is omitted in order to provide a clear view other stairway 800 elements, and the positioning and functioning of said omitted inside bracket 826 will be understood by reference to said earlier specification materials and FIGS. 1A, 1B, 2, 3, 4, 5. FIG. 8 illustrates an alternative locking and support structure for the stairway 800, which is also adaptable for use and incorporation within the stairway 100 illustrated in FIGS. 1A, 1B, 2, 3, 4, 5 and 6 and described above. The stairway 800 is configured to be movable, and more particularly to be pivoted upward about the pivot bolt 828, enabling the stairway 800 to be stored upward in a fashion similar to that as shown in FIG. 1B with respect to stairway 100, when not deployed downward for use as shown in FIG. 8. Thus in one example adapted for use in boarding a boat deck from a dock incorporating a base structural element 805, the stairway 800 may be moved up and back over the dock and out of the way of the water or the boat: the entire stairway 800 thus pivoted to the left of a vertical axis NN normal to a horizontal orientation HH and extending upward from inside edges of the pair of mounting brackets 826.

In one embodiment the stairway 800 is configured so that when pivoted upward and into a stowed or non-deployed position (with a vertical orientation similar to that illustrated in FIG. 1B with respect to stairway 100, the support beam 802 making an angle θθ with the horizontal ground orientation greater than 90 degrees, the support beam 802 forming a positive angle δδ with vertical axis NN) a front edge 803 of the support beam 802 rests against at least one stopper means 809 attached to at least one of the support bracket(s) 826 (in FIG. 8, it will be understood that the stopper means 809 is attached to the omitted support bracket 826). In the present embodiment the stopper means 809 is an adjustable cam support element 809. In the present example the support beam 802 is supported by the stopper means 809 wherein the front edge 807 a of a bottom stairstep tread 806 a remains spaced from the base step element 813, which in some embodiments may be attached directly to decking boards board or other base surface(s) (not shown). Thus the weight of the stairway assembly 800 when upright is supported by the at least one adjustable cam support element 809, and said weight support or vertical alignment of the stairway 800 when stowed upright is not dependent upon interaction with or the orientation of the base step element 813. By using an eccentric cam means 809 additional advantages are provided by enabling adjustment of the upright/stowed resting position of the stair 800 through rotation, replacement or other adjustment of the cam means 809, and will be readily understood by one skilled in the art. It will also be appreciated that and other non-cam rest or stopper means 809 may also be utilized (not shown).

Supporting the stowed/upright stairway 800 independent of interaction of the bottom stairstep tread edge 807 a with a base step element 813 or other base structure connected to the ground or other supporting mass provides advantages in assuring the integrity of the assembly 800 deployment, removing failure possibilities or alignment irregularity issues which may otherwise occur, for example through failure of the base step element 813 or movement of the base step element 813 through temperature and seasonal variations (e.g. through expansion through high temperatures or movement through frost-heave of the base step element 813 or other associated structural elements).

The stairway 800 incorporates locking and/or restraining means for both maintaining the stairway 800 in the downward deployed position shown in FIG. 8 (and similar to the view illustrated in FIG. 1A with respect to stairway 100) by stopping the support beam 802 from pivoting upward about the pivot bolt 828 thereby preventing movement of the stairway assembly 800 upward and backward, and also by stopping the support beam 802 from pivoting downward about the pivot bolt 828 thereby preventing movement of the stairway assembly 800 downward and into a deployed position from the upward/stowed position. FIG. 9 provides a side view of the bottom area illustrated in FIG. 8 as partially disassembled and with portions of the stairway 800 omitted for clarity. Referring to both FIGS. 8 and 9 the restraining means comprises a lock bar 864 pivotally connected to a connection block 866 attached to the top surface 827 of the rectangular support beam 802, and a spring-loaded lock bar arm 862 rotatably attached to the lock bar 864 and extending horizontally and generally aligned with the horizontal orientation HH, the lock bar arm 862 configured to urge the lock bar 864 inward along a locking direction vector LD. The support beam top surface 827 further defines an aperture slot 876 projecting inward from the support beam bottom edge 803 and configured to allow the lock bar 864 to pivot downward under urging of the lock bar arm 862 into an inward negative-vertical locking position (as may also be understood by referring to the aperture 127 illustrated in FIG. 3 and described above).

When the stairway 800 is in a deployed position for walking upon as illustrated in FIG. 8 (or as understood by reference to the stairway 100 as illustrated in FIGS. 1A and 3 and described above) the spring-loaded lock bar arm 862 urges the lock bar 864 to form an angle 807 with a vertical axis orientation NN, with the bottom edge 875 of the lock bar 864 spaced above the top surface 811 of a reinforcing plate 880 attached to a base mounting plate 801 a spacing distance 882. In one embodiment the angle 807 is from about six degrees to about seven degrees, though other angle 807 values may be practiced, and in some embodiments the spacing distance 882 is from about 0.005 inches to about 0.007 inches, though other spacing distances 882 may be practiced. In the lock bar 864 positioned as thus described (and illustrated in FIGS. 8 and 9) pivoting the stair 800 upward about the pivot bolt 828 urges the lock bar bottom surface to travel downward through the spacing gap 882 and into the reinforcing plate top surface 811, this contact stopping further upward pivoting about the pivot bolt 828. Thus forces pivoting the support beam 802 upward and about the pivot bolt 828 are translated by the pivot bolt 828 to drive the lock bar bottom edge 875 into the reinforcing plate top surface 111.

In one advantage the angle 807 causes the lock bar 864 to be pivoted and driven toward the reinforcing plate surface 811 with vector component forces along the inward locking directional vector DL in response to forces raising the stair 800 about the stair pivot bolt 828, further urging the lock bar 864 into engagement with the reinforcing plate 880 and also preventing the lock bar bottom edge 875 from moving in an opposite direction to the vector DL and slipping off of the reinforcing plate surface 811 and dropping into a gap 870 defined between stair 800 base elements and the base step element 813 and thereby out of locking engagement with the reinforcing plate 880, for example if the lock bar arm 862 spring-loaded means (now shown) were to fail to adequately urge the lock bar 864 inward. In one advantage as forces acting on the stairway 800 in an upward pivot direction increase, these forces are translated by the pivot bolt 828 into increasing forces driving the lock arm bottom edge 875 further into the reinforcing plate top surface 811 and therefore further urging said bottom edge 875 to move inward along the direction of vector DL, which also increases frictional forces that must be overcome to slide the lock arm bottom edge 875 along the reinforcing plate top surface 811 in an opposite direction to release the lock bar 864 from the engaging and locking alignment shown in FIGS. 8 and 9.

The lock bar arm 862 is also configured to move outward and in a direction opposite to the lock-engaging direction vector LD, the lock bar arm 862 causing the locking bar 864 to responsively pivot outward and move the bar bottom edge 875 out of alignment with the upper plate surface 811 and enabling the lock bar 864 to drop downward into the spacing gap 870 with pivoting of the stairway 800 upward toward the stowed/vertical alignment (or as may be understood by reference to the stairway 100 as illustrated in FIGS. 1B and 4 and described above). The locking bar arm 862 may be engaged directly by an operator, for example by a hand or a foot, through an attachment as a rope or a cable, or through some other operative mechanical means, the arm 862 thereby compelled outward/backward and causing the lock bar 864 to pivot outward. In the present embodiment a foot-petal means 898 is attached to the first step element 813 structure and connected to the lock bar arm 862, wherein pushing a foot pedal 899 inward along the direction LD causes the lock bar arm 862 to be leveraged backward in an opposite direction, though other mechanical means may be practiced.

In the present example movement of the lock bar 864 outward/backward is further enabled by the spacing gap 882 between the lock bar bottom edge 875 and the reinforcing plate top surface 811. More particularly, the spacing gap 882 provides for movement of the lock bar arm bottom edge 875 inwardly or outwardly without contacting, and thus without interference by, the reinforcing plate top surface 811.

Referring now to FIG. 10, the lock bar 864 is further configured to engage a bottom reinforcing plate 884 and thereby lock the stairway 800 into a stowed/upward position (as may be understood by reference to the stairway 100 as illustrated in FIGS. 1B and 4 and described above). More particularly, when the stair 800 is deployed in said stowed/upward position with the lock bar 864 dropped down into the bar-accepting gap 870 the spring-loaded lock bar arm 862 drives an internal lock bar notch surface 889 into contact with either or both of a bottom reinforcing plate 884 inner edge 887 or a upper reinforcing plate 880 inner edge 885 along spring-loaded force vector DL. Thus aligned a lock bar lower lip locking surface 888 is disposed below the bottom surface 886 of the bottom reinforcing plate 884 and spaced a lip distance 890.

In the lock bar 864 positioned as thus described and illustrated in FIG. 10 pivoting the stair 800 downward about the pivot bolt 828 toward deploying the stair 800 (as illustrated in FIGS. 8 and 9 and described above) urges the lock bar lip 888 to travel upward through the lip spacing gap 890 and into the reinforcing bottom plate bottom surface 890, this contact stopping further downward pivoting about the pivot bolt 828. Thus forces pivoting the support beam 802 downward and about the pivot bolt 828 are translated by the pivot bolt 828 to drive the lock bar lip edge 888 into the reinforcing bottom plate 886.

In the present example movement of the lock bar 864 outward/backward from the locking engagement illustrated in FIG. 10 is further enabled by the lip spacing gap 890: more particularly, the lip spacing gap 890 provides for movement of the lock bar lip edge 888 inwardly or outwardly without contacting, and thus without interference by, the bottom reinforcing plate bottom surface 886. The lip edge surface 888 is also oriented at an angle 892 with the horizontal orientation HH, which enables a linear edge 893 of the lip 888 to be driven into the bottom reinforcing plate bottom surface 886 responsive to pivoting the stair 800 downward about the pivot bolt 828 toward deployment: concentrating contact forces on this linear edge 893 increases engagement forces fixed the lock bar lip 888 into engagement with the bottom reinforcing plate bottom surface 886, thus further increasing the locking characteristics of the lock bar lip 888, for example enabling the lip 888 to “hook” into the bottom reinforcing plate bottom surface 886 and further resist slipping from engagement thereto. In some embodiments the lip angle 892 is about 10 degrees, though other angles 892 may be practiced.

In another aspect the stair assembly 800 is attached to a riser block structure 805 which is itself attached to the base ground structure G, such as a dock, etc. More particularly, in some embodiments the riser block 805 and the base step element 813 are configured to form a first step height for a user of the stair 800 as installed and deployed in the downward (FIG. 8 and 9) position, the riser block 805 and the base step element 813 thus providing a clearance space between the mounting brackets 826 and a base area to which the assembly is attached, enabling access for adjustment, installation and other servicing operations with respect to the locking mechanisms described herein, and further readily enabling operative movement of the lock bar arm 862 and lock bar 864 without interference with ground structures and linkage of various mechanical means (such as a foot petal mechanism, not shown) to the lock arm bar 862 for controlling operative movement of said lock arm bar 862.

The foregoing description of various aspects of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously, many modifications and variations are possible. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of the invention as defined by the accompanying claims. The invention has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be constructed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. 

1. A stairway, comprising: a support beam; a plurality of stair treads attached to said beam; a pair of mounting brackets disposed at either side of a support beam bottom end and rotatably connected to the support beam by a pivot bolt, the mounting brackets further connected to a base, the base connected to a load bearing structure; a support bolt disposed through the mounting brackets and below a bottom surface of the support beam; and a locking means pivotally connected to the support beam and configured to engage a base mounting plate and thereby restrain the stairway from at least one of pivoting upward about the pivot bolt or pivoting downward about the pivot bolt; wherein the support beam is configured to pivot downward about the pivot bolt to rest upon the support bolt in a downward deployment and pivot upward about the pivot bolt into a non-deployed orientation; and wherein the support beam is configured to transfer operative loads upon the stair treads aligned in the support beam downward deployment and with an opposite upper support beam end unsupported from the support beam bottom end through leverage into the support brackets through the pivot bolt and support bolt, the support brackets thereby configured to transfer all the stair tread operative loads through the base into the load bearing structure, and wherein said upper beam end is free of connection to the base or the load bearing structure or any other operative load-supporting structure.
 2. The stairway of claim 1, the pivotally connected locking means comprising a lock bar having a top end and a bottom edge, the lock bar top end defining a bolt aperture, and a pivot bolt rotatably conveyed through the pivot bolt aperture; the support beam defining an aperture slot projecting inward from a support beam bottom edge and configured to allow the lock bar to pivot downward and into the aperture; and the stairway further comprising a mounting plate disposed between the support brackets and the base; wherein the lock bar is configured to hang downward from the pivot bolt within the support beam aperture slot and form an inward negative vertical locking position angle with respect to a vertical orientation parallel to a gravitational force vector, the lock bar bottom edge thereby aligned above and spaced from a top surface of the base mounting plate, and wherein pivoting of the support beam upwards about the pivot bolt causes the lock bar bottom edge to be driven into base mounting plate top surface, the lock bar thereby constraining the stairway support beam from moving upward.
 3. The stairway of claim 2 wherein the inward negative vertical locking position angle is chosen to cause the lock bar bottom edge to be pivoted and driven toward and along the bottom plate surface along an angle vector component in response to forces raising the stair upward about the pivot bolt, the vector component urging the lock bar bottom edge into engagement with the bottom plate surface and thereby preventing the lock bar bottom edge from moving in a direction opposite to the angle vector component and slipping off of the plate surface and out of an engagement with the plate surface.
 4. The stairway of claim 3, the base structure comprising a riser, the riser configured to enable access to the locking means and to enable operative movement of the locking means without interference with the load bearing structure; and a first step connected to the riser and spaced a lock bar receiving gap from the support brackets and the base mounting plate; wherein the lock bar is configured to pivot outward and away from alignment of the lock bar bottom edge over the mounting plate top surface and to drop into the lock-arm receiving gap when the stairway is lifted upward.
 5. The stairway of claim 4 further comprising at least one support beam bottom edge stopper attached to at least one of the support brackets, wherein the support beam bottom edge rests against the stopper when the stairway is deployed in an upward/stowed position with a bottommost stair tread front edge spaced from the first step.
 6. The stairway of claim 5 wherein the at least one support beam bottom edge stopper is an eccentric cam.
 7. The stairway of claim 6 wherein the lock bar bottom edge spacing distance is from about 0.005 inches to about 0.007 inches, and the inward negative vertical locking position angle is from about six degrees to about seven degrees from the vertical orientation.
 8. The stairway of claim 7 wherein the lock bar pivot bolt aperture is formed off-center in the lock bar top end more proximate to an inside edge of the lock bar then a lock bar outside edge arrayed facing the lock bar receiving gap, the off-center alignment configured to cause the lock bar to hang downward from the pivot bolt and form the inward negative vertical locking position angle in response to gravitational forces acting on the lock bar along the vertical orientation.
 9. The stairway of claim 7, further comprising: a lock bar arm rotatably attached to the lock bar; spring-loaded means attached to the lock bar arm and configured to urge the lock bar arm and the lock bar inward toward the mounting plate; and a pedal means attached to the lock bar arm and configured to move the lock bar arm and the lock bar outward away from mounting plate in response to a user pushing the pedal means, the outward lock bar movement causing the lock bar to pivot outward and into an alignment enabling the lock bar to drop downward into the lock-bar spacing gap with pivoting of the stairway upward.
 10. The stairway of claim 9, the lock bar further comprising an internal lock bar notch having a lower lip; wherein the spring-loaded lock bar arm is configured to drive an internal lock bar notch surface into contact with an inner edge surface of the base mounting plate and dispose the notch lip spaced below a base mounting plate lower surface a lip spacing distance.
 11. The stairway of claim 10 wherein the lower lip is oriented at a positive angle with a horizontal orientation normal to the vertical orientation.
 12. The stairway of claim 10 wherein the lower lip horizontal orientation angle is about 10 degrees.
 13. A method for supporting a stairway at only one bottom end, comprising: disposing a plurality of stair treads along a support beam; rotatably connecting a pair of mounting brackets at either side of a support beam bottom end through a pivot bolt; connecting the mounting brackets to a base; connecting the base to a load bearing structure; disposing a support bolt through the mounting brackets and below a bottom surface of the support beam; pivotally connecting a locking means to the support beam; the locking means engaging a base mounting plate and thereby restraining the stairway from at least one of pivoting upward about the pivot bolt or pivoting downward about the pivot bolt; the support beam pivoting downward about the pivot bolt to rest upon the support bolt in a downward deployment and pivoting upward about the pivot bolt into a non-deployed orientation; and the support beam transferring operative loads from the stair treads aligned in the support beam downward deployment and with an opposite upper support beam end unsupported from the support beam bottom end through leverage into the support brackets through the pivot bolt and support bolt, the support brackets thereby transferring all the stair tread operative loads through the base into the load bearing structure, the upper beam end free of connection to the base or the load bearing structure or any other operative load-supporting structure.
 14. The method of claim 13, the pivotally connected locking means comprising a lock bar having a top end and a bottom edge; the lock bar top end defining a bolt aperture; a pivot bolt rotatably connecting the lock bar top end to a lock means base block through the pivot bolt aperture; the support beam defining an aperture slot projecting inward from a support beam bottom edge and configured to allow the lock bar to pivot downward and into the aperture; and disposing a mounting plate between the support brackets and the base; the lock bar hanging downward from the pivot bolt within the support beam aperture slot and forming an inward negative vertical locking position angle with respect to a vertical orientation parallel to a gravitational force vector, a lock bar bottom edge thereby aligned above and spaced from a top surface of the base mounting plate, and wherein pivoting of the support beam upwards about the pivot bolt causes the lock bar bottom edge to be driven into base mounting plate top surface, the lock bar thereby constraining the stairway support beam from moving upward.
 15. The method of claim 14, comprising: the inward negative vertical locking position angle causing the lock bar bottom edge to be pivoted and driven toward and along the bottom plate surface along an angle vector component in response to forces raising the stair upward about the pivot bolt; and the vector component urging the lock bar bottom edge into engagement with the bottom plate surface and preventing the lock bar bottom edge from moving in a direction opposite to the angle vector component and slipping off of the plate surface and out of an engagement with the plate surface.
 16. The method of claim 15, comprising: a base structure a riser enabling access to the locking means and operative movement of the locking means without interference with the load bearing structure; and disposing a first step connected to the riser spaced a lock bar receiving gap from the support brackets and the base mounting plate; wherein the lock bar is configured to pivot outward and away from alignment of the lock bar bottom edge over the mounting plate top surface and to drop into the lock-arm receiving gap when the stairway is lifted upward.
 17. The method of claim 16 further comprising the support beam bottom edge resting against at least one support beam bottom edge stopper attached to at least one of the support brackets with a bottommost stair tread front edge spaced from the first step when the stairway is deployed in an upward/stowed position.
 18. The method of claim 17, comprising: forming the lock bar pivot bolt aperture off-center in the lock bar top end more proximate to an inside edge of the lock bar then a lock bar outside edge arrayed facing the lock bar receiving gap; the off-center alignment causing the lock bar to hang downward from the pivot bolt and form the inward negative vertical locking position angle in response to gravitational forces acting on the lock bar along the vertical orientation.
 19. The method of claim 17, comprising: rotatably attaching a lock bar arm to the lock bar; attaching a spring-loaded means to the lock bar arm; the spring-loaded means urging the lock bar arm and the lock bar inward toward the mounting plate; and attaching a pedal means to the lock bar arm, the pedal means configured to move the lock bar arm and the lock bar outward away from mounting plate in response to a user pushing the pedal means, said outward lock bar movement causing the lock bar to pivot outward and into an alignment enabling the lock bar to drop downward into the lock-bar spacing gap with pivoting of the stairway upward.
 20. The method of claim 19, comprising: the lock bar defining an internal lock bar notch having a lower lip; the spring-loaded lock bar arm driving an internal lock bar notch surface into contact with an inner edge surface of the base mounting plate and disposing the notch lip spaced below a base mounting plate lower surface a lip spacing distance, the lower lip oriented at a positive angle with a horizontal orientation normal to the vertical orientation. 